VCBM 2020: Eurographics Workshop on Visual Computing for Biology and Medicine
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Browsing VCBM 2020: Eurographics Workshop on Visual Computing for Biology and Medicine by Subject "Computing methodologies"
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Item Aneulysis - A System for Aneurysm Data Analysis(The Eurographics Association, 2020) Meuschke, Monique; Wickenhöfer, Ralph; Preim, Bernhard; Lawonn, Kai; Kozlíková, Barbora and Krone, Michael and Smit, Noeska and Nieselt, Kay and Raidou, Renata GeorgiaWe present ANEULYSIS, a system to improve risk assessment and treatment planning of cerebral aneurysms. Aneurysm treatment must be carefully examined as there is a risk of fatal outcome during surgery. Aneurysm growth, rupture, and treatment success depend on the interplay of vascular morphology and hemodynamics. Blood flow simulations can obtain the patient-specific hemodynamics. However, analyzing the time-dependent, multi-attribute data is time-consuming and error-prone. ANEULYSIS supports the analysis and visual exploration of aneurysm data including morphological and hemodynamic attributes. Since this is an interdisciplinary process involving both physicians and fluid mechanics experts, we provide a redundancy-free management of aneurysm data sets according to a consistent structure. Major contributions are an improved analysis of morphological aspects, simultaneous evaluation of wall- and flow-related characteristics as well as multiple attributes on the vessel wall, the assessment of mechanical wall processes as well as an automatic classification of the internal flow behavior. It was designed and evaluated in collaboration with domain experts who confirmed its usefulness and clinical necessity.Item InShaDe: Invariant Shape Descriptors for Visual Analysis of Histology 2D Cellular and Nuclear Shapes(The Eurographics Association, 2020) Agus, Marco; Al-Thelaya, Khaled; Cali, Corrado; Boido, Marina M.; Yang, Yin; Pintore, Giovanni; Gobbetti, Enrico; Schneider, Jens; Kozlíková, Barbora and Krone, Michael and Smit, Noeska and Nieselt, Kay and Raidou, Renata GeorgiaWe present a shape processing framework for visual exploration of cellular nuclear envelopes extracted from histology images. The framework is based on a novel shape descriptor of closed contours relying on a geodesically uniform resampling of discrete curves to allow for discrete differential-geometry-based computation of unsigned curvature at vertices and edges. Our descriptor is, by design, invariant under translation, rotation and parameterization. Moreover, it additionally offers the option for uniform-scale-invariance. The optional scale-invariance is achieved by scaling features to z-scores, while invariance under parameterization shifts is achieved by using elliptic Fourier analysis (EFA) on the resulting curvature vectors. These invariant shape descriptors provide an embedding into a fixed-dimensional feature space that can be utilized for various applications: (i) as input features for deep and shallow learning techniques; (ii) as input for dimension reduction schemes for providing a visual reference for clustering collection of shapes. The capabilities of the proposed framework are demonstrated in the context of visual analysis and unsupervised classification of histology images.Item Learning Hand Anatomy with Sense of Embodiment(The Eurographics Association, 2020) Saalfeld, Patrick; Albrecht, Aylin; D'Hanis, Wolfgang; Rothkötter, Hermann-Josef; Preim, Bernhard; Kozlíková, Barbora and Krone, Michael and Smit, Noeska and Nieselt, Kay and Raidou, Renata GeorgiaWe present a VR-based prototype for learning the hand anatomy. The prototype is designed to support embodied cognition, i.e., a learning process based on movements. The learner employs the prototype in VR by moving their own hand and fingers and observing how the virtual anatomical hand model mirrors this movement. The display of anatomical systems and their names can be adjusted. The prototype is deployed on the Oculus Quest and uses its native hand tracking capabilities to obtain the hand posture of the user. The potential of the prototype is shown with a small user study.Item Real-Time Visualization of 3D Amyloid-Beta Fibrils from 2D Cryo-EM Density Maps(The Eurographics Association, 2020) Kniesel, Hannah; Ropinski, Timo; Hermosilla, Pedro; Kozlíková, Barbora and Krone, Michael and Smit, Noeska and Nieselt, Kay and Raidou, Renata GeorgiaAmyloid-beta fibrils are the result of the accumulation of misfolded amyloid precursor proteins along an axis. These fibrils play a crucial role in the development of Alzheimer's disease, and yet its creation and structure are not fully understood. Visualization is often used to understand the structure of such fibrils. Unfortunately, existing algorithms require high memory consumption limiting their applications. In this paper, we introduce a ray marching algorithm that takes advantage of the inherent repetition in these atomic structures, requiring only a 2D density map to represent the fibril. During ray marching, the texture coordinates are transformed based on the position of the sample along the longitudinal axis, simulating the rotation of the fibrils. Our algorithm reduces memory consumption by a large margin and improves GPU cache hits, making it suitable for real-time visualizations. Moreover, we present several shading algorithms for this type of data, such as shadows or ambient occlusion, in order to improve perception. Lastly, we provide a simple yet effective algorithm to communicate the uncertainty introduced during reconstruction. During the evaluation process, we were able to show, that our approach not only outperforms the Standard Volume Rendering method by significantly lower memory consumption and high image quality for low resolution 2D density maps but also in performance.Item Student and Teacher Meet in a Shared Virtual Reality: A one-on-one Tutoring System for Anatomy Education(The Eurographics Association, 2020) Saalfeld, Patrick; Schmeier, Anna; D'Hanis, Wolfgang; Rothkötter, Hermann-Josef; Preim, Bernhard; Kozlíková, Barbora and Krone, Michael and Smit, Noeska and Nieselt, Kay and Raidou, Renata GeorgiaWe introduce a Virtual Reality (VR) one-on-one tutoring system to support anatomy education. A student uses a fully immersive VR headset to explore the anatomy of the base of the human skull. A teacher guides the student by using the semi-immersive zSpace. Both systems are connected via network and each action is synchronized between both systems. The teacher is provided with various features to direct the student through the immersive learning experience. The teacher can influence the student's navigation or provide annotations on the fly and hereby improve the student's learning experience.Item The Virtual Reality Flow Lens for Blood Flow Exploration(The Eurographics Association, 2020) Behrendt, Benjamin; Piotrowski, Lisa; Saalfeld, Sylvia; Preim, Bernhard; Saalfeld, Patrick; Kozlíková, Barbora and Krone, Michael and Smit, Noeska and Nieselt, Kay and Raidou, Renata GeorgiaThe exploration of time-dependent measured or simulated blood flow is challenging due to the complex three-dimensional structure of vessels and blood flow patterns. Especially on a 2D screen, understanding their full shape and interacting with them is difficult. Critical regions do not always stand out in the visualization and may easily be missed without proper interaction and filtering techniques. The FlowLens [GNBP11] was introduced as a focus-and-context technique to explore one specific blood flow parameter in the context of other parameters for the purpose of treatment planning. With the recent availability of affordable VR glasses it is possible to adapt the concepts of the FlowLens into immersive VR and make them available to a broader group of users. Translating the concept of the Flow Lens to VR leads to a number of design decisions not only based around what functions to include, but also how they can be made available to the user. In this paper, we present a configurable focus-and-context visualization for the use with virtual reality headsets and controllers that allows users to freely explore blood flow data within a VR environment. The advantage of such a solution is the improved perception of the complex spatial structures that results from being surrounded by them instead of observing through a small screen.Item VirtualDSA++: Automated Segmentation, Vessel Labeling, Occlusion Detection and Graph Search on CT-Angiography Data(The Eurographics Association, 2020) Thamm, Florian; Jürgens, Markus; Ditt, Hendrik; Maier, Andreas; Kozlíková, Barbora and Krone, Michael and Smit, Noeska and Nieselt, Kay and Raidou, Renata GeorgiaComputed Tomography Angiography (CTA) is one of the most commonly used modalities in the diagnosis of cerebrovascular diseases like ischemic strokes. Usually, the anatomy of interest in ischemic stroke cases is the Circle of Willis and its peripherals, the cerebral arteries, as these vessels are the most prominent candidates for occlusions. The diagnosis of occlusions in these vessels remains challenging, not only because of the large amount of surrounding vessels but also due to the large number of anatomical variants. We propose a fully automated image processing and visualization pipeline, which provides a full segmentation and modelling of the cerebral arterial tree for CTA data. The model itself enables the interactive masking of unimportant vessel structures e.g. veins like the Sinus Sagittalis, and the interactive planning of shortest paths meant to be used to prepare further treatments like a mechanical thrombectomy. Additionally, the algorithm automatically labels the cerebral arteries (Middle Cerebral Artery left and right, Anterior Cerebral Artery short, Posterior Cerebral Artery left and right) detects occlusions or interruptions in these vessels. The proposed pipeline does not require a prior non-contrast CT scan and achieves a comparable segmentation appearance as in a Digital Subtraction Angiography (DSA).